Land-water linkages and the biogeochemistry and ecology of Arctic aquatic ecosystems

陆地与水的联系以及北极水生生态系统的生物地球化学和生态学

• 批准号: 430696-2013
• 负责人: Tank, Suzanne
• 金额: $ 1.05万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=552591
• 关键词: Land; water; linkages; biogeochemistry; ecology

Rivers and lakes are powerful integrators of the landscapes that surround them. Changes on land are inevitably captured by water flowing across landscapes, which is ultimately delivered to aquatic environments. Thus, aquatic ecosystems both capture, and are affected by, change occurring across broad spatial scales. This is particularly important in the north because permafrost - the permanently frozen ground that covers about half of Canada's landmass - is thawing throughout the Arctic. Thus, constituents currently 'locked away' (sequestered) in permafrost are becoming available for reaction within and liberation from soils, and transport to aquatic environments. Working at sites experiencing massive permafrost slumping in the western Canadian Arctic, this research will examine how permafrost thaw changes the land-to-water flux of dissolved inorganic and organic carbon (DIC, DOC), and the implications of this change for the larger carbon (C) cycle. Bicarbonate, which is typically the main component of the aquatic DIC pool, is largely produced by chemical weathering, whereby CO2 dissolved in water reacts with the mineral component of soils, causing the original CO2 to become 'fixed' as bicarbonate. Alongside photosynthesis, weathering is one of two main sequestration mechanisms for CO2 on land. In contrast, permafrost soils contain about twice as much organic C as currently exists in the atmosphere as CO2, and thus DOC mobilized from thawing permafrost represents a future CO2 source, following its degradation by bacteria or sunlight. Although research exploring the C dynamics of permafrost thaw has focused almost exclusively on organic C degradation, our early work has shown that increased weathering in newly-thawed mineral soils may temper the effect of CO2 release from organic C as permafrost thaws. This research will undertake a unique, concurrent investigation of the counterbalancing effects of permafrost thaw on inorganic and organic C cycling in the western Canadian Arctic, and train multiple southern personnel and northern residents. Because of the many constituents released as permafrost thaws, this work will also bolster understanding of the socio-economic and environmental effects of permafrost thaw on northern freshwaters.

河流和湖泊是它们周围景观的强大综合体。陆地上的变化不可避免地被流经地貌的水捕获，最终传递到水环境中。因此，水生生态系统既捕捉到了广泛空间尺度上发生的变化，也受到了这种变化的影响。这在北部尤其重要，因为永久冻土--覆盖加拿大陆地约一半的永久冻土--正在整个北极融化。因此，目前在永久冻土中被“锁定”(隔离)的成分正变得可用于土壤内的反应和从土壤中释放，并转移到水生环境中。这项研究工作在加拿大西部北极地区经历了大规模永久冻土崩塌的地点，将研究永久冻土融化如何改变溶解的无机和有机碳(DIC，DOC)的陆地到水的通量，以及这种变化对更大的碳(C)循环的影响。碳酸氢盐通常是水生DIC池的主要成分，主要是由化学风化作用产生的，即溶解在水中的二氧化碳与土壤的矿物成分发生反应，导致最初的二氧化碳成为重碳酸盐。除光合作用外，风化作用是陆地上二氧化碳的两种主要封存机制之一。相比之下，永冻土含有的有机碳大约是目前大气中二氧化碳含量的两倍，因此从融化的永冻土中动员的DOC代表着未来的二氧化碳来源，仅次于细菌或阳光对其的降解。尽管探索冻土融化的碳动态的研究几乎完全集中在有机碳的降解上，但我们的早期工作表明，随着冻土融化，新解冻矿物土壤的风化程度增加可能会缓和有机碳释放二氧化碳的影响。这项研究将对加拿大西部北极地区永久冻土融化对无机和有机碳循环的平衡影响进行一项独特的同时调查，并培训多名南方人员和北方居民。由于多年冻土融化时释放出许多成分，这项工作还将有助于理解永久冻土融化对北方淡水的社会经济和环境影响。